Georg Henrik von Wright’s Norm and Action represents a significant step in the development of deontic logic. By introducing the ideas of action and change into the system of formal logic, von Wright is able to bring the idea of norms, especially prescriptions which govern actions, under logical consideration. Much of the volume covers the development of a formal vocabulary of symbolic logic, though careful consideration is also given to the informal language in which norms are typically expressed, as well as to the hierarchical structures within which norms are typically formulated.